1. Field of the Invention
The present invention relates to a safety ski binding adapted to hold the front of a boot on a ski.
2. Description of Background Information
Safety ski bindings of this type are called "front abutments", and include a body supporting in its rear part a jaw for holding the front of the boot. The jaw may be of the monoblock type or constituted of two independent lateral retention wings which are respectively journalled on the body about individual axes. Moreover, the body of the front abutment contains an energization mechanism for returning the jaw to the central locking position and which comprises a compression spring and a force transmission element, such as a tie rod or a sliding piston, which is inserted between the spring and the jaw. The spring rests at one of its ends on a support surface whose longitudinal position is adjustable by means of a screw for adjustment of the stiffness of the binding, and it acts through its other end on the force transmission element.
Front abutments of this type, in which the energization mechanism includes a shock absorber joined in parallel to the compression spring, are known. This additional shock absorber makes it possible to vary the release threshold of the front abutment with respect to the duration of the biasing. The threshold is elevated for brief biases and, on the other hand, is relatively weak for biases of long duration. This makes it possible to better adapt the response of the front abutment to the characteristics of mechanical resistance of the leg of a skier which can resist a bias of violent or elevated, but brief, intensity, whereas the leg can break in the case of a bias of weak intensity that is exerted during a fairly long period of time.
A front abutment which comprises a shock absorber joined to a compression spring forming part of the energization mechanism is described in German Patent No. 2,415,957 which includes, in one embodiment, a shock absorber which is coaxially mounted to the interior of the compression spring forming part of the energization mechanism. Such an arrangement is in fact preferable because it makes it possible to substantially reduce the bulk of the energization mechanism assembly. However, with such an arrangement, it is difficult to be able to adjust the stiffness of the energization spring, i.e., the initial rate of compression, without also modifying the initial length of the shock absorber at rest. With such a construction, it is necessary that the maximum course of compression of the shock absorber be at least equal to the sum of the compression course of the energization spring corresponding to the release of the binding and the compression course of the spring corresponding to the distance for adjustment of the stiffness of the spring. Another disadvantage of this type of front abutment is that it does not permit limiting the increase of the value of the release threshold in the case of a brief and intense bias which leads to the blocking of the shock absorber.